The node Careful Assault of Shadow Cascade makes the skill do more damage if you have a specific number of Shadows. This influences the DPS shown in the skill tooltip in certain cases.
For this example, we imagine that the DPS of Shadow Cascade is 5000 and that we have invested two points into Careful Assault. Upon logging into the game, the tooltip shows 5000 DPS. Now we cast Synchronized Strike, which creates two Shadows. The tooltip still shows 5000 DPS. Then we attack with Shadow Cascade, which will do 50% more damage, because we have two Shadows. Now the tooltip will show 7500 DPS until we attack again with Shadow Cascade, which will reset it to 5000.
This isn’t necessarily wrong, but I would have expected the DPS tooltip to not be influenced by such a situational modifier.